1. Field of the Invention
The present invention relates to an antenna, more particularly, to an antenna with compact size and low cost.
2. The Related Art
The mobile phone has become one of essential apparatuses in daily lives nowadays. According to progress of the mobile and marketing request, there are various types of functions, such as taking a picture, playing music, recording voice, recording video, playing games, receiving broadcast, etc, embedded in the mobile phone. The functions mentioned above have become essential functions of the mobile phone.
For an instance of receiving broadcast, the mobile phone need an antenna for receiving broadcast signal and a means for processing the received broadcast signal. Because the broadcast bands cover the range from hundreds KHz to hundreds MHz, the length of the antenna capable of receiving broadcast signal needs to be from one meter to several meters.
Thus, the antenna capable of receiving broadcast signal has a certain size. Considering the compact size is a necessary element for the mobile phone, it is difficult to manufacture the antenna embedded in the mobile phone to be capable of receiving broadcast signal.
An embedded broadcast receiving antenna is disclosed at Taiwan patent M320194. The Taiwan patent discloses a FM antenna has a ceramic body and a microstrip conductor disposed on the ceramic body. The ceramic body is of a rectangle shape. The microstrip conductor is of a helix shape and winded on surfaces of the ceramic body.
The ceramic body in prior art is made of ceramic material with high dielectric constant for the purpose of shortening the length of the microstrip conductor. Thus, the FM antenna can be a small size and is likely to be well-configured in the mobile phone. However, the FM antenna has high cost due to the high cost of the ceramic material.
A further type of the FM antenna is shown from U.S. Pat. No. 7,064,720. The U.S. patent discloses an earphone antenna having an earphone unit including an earphone, an earphone cable for supplying audio signals to the earphone, and a first pin jack connector portion on one end of the earphone cable, the earphone cable functioning as an antenna wire.
Because the earphone cable functions as an antenna wire, the mobile phone must connect the earphone antenna for receiving FM signal from the earphone antenna and processing the FM signal. The earphone phone antenna has the following defects: It is inconvenient to carry the earphone antenna all the time. The size of the earphone antenna can hardly be reduced. Moreover, it takes more cost and longer repairing time.